Content, such as media content or applications, may be produced for consumption and enjoyment by consumers. For example, movies may be produced that consumers pay to see in cinemas, music is sold to consumers on compact disks, CDs, and digital versatile disks, DVDs, provide a format usable for renting movies to consumers from video rental stores. In the same way applications might be downloaded and enjoyed by the consumer e.g. games.
Content delivered in digital format over a communication network presents challenges to copyright owners, since media files in computer-readable format are easy to copy and reproduce. Unlicensed copying may reduce revenues from commercially produced content, whereby measured may be taken to reduce the ease of copying content in computer-readable format. On the other hand, consumers wish to use their legally obtained content not just on the device they used to obtain the content and do not wish to pay several times for it.
The content scrambling system, CSS, is a DRM solution that relies on encryption to prevent copying of content of DVD discs. In CSS, a DVD disk comprises an encrypted disk-specific key encoded on the disk, which a DVD player can decrypt using a special CSS key. The contents of the DVD disk can then be decrypted using the decrypted disk-specific key.
Region-coding is another approach to DRM. Under region coding, media carriers of content are encoded with a code specific to a region, such as for example Europe. Content players, such as for example DVD players, are likewise region-coded, with the region coding corresponding to the region where the content players are sold. Therefore, a content player purchased in Europe may be configured to play content encoded on media carriers that have the same encoding. As a consequence, a content player purchased in Europe may agree to play content from media carriers likewise purchased in Europe. This reduces illicit trade in media carriers, since media carriers from China, for example, could not be used in Europe. In some instances, a content player allows modifying the region coding a limited number of times to allow for moving between regions.
In cable or satellite television, a media stream delivered to households may be encrypted to prevent viewing without payment. In order to enable paying customers to view the stream, the customer may be provided with a smart card, for example, which comprises decryption keys needed to view the stream. In detail, the smart card may be installed in a cable or satellite receiver to enable decryption of the encrypted media stream.
Much like DRM, controlling access to otherwise sensitive information involves questions relating to encryption and usability. Information may be sensitive due to privacy, legal, commercial, political or military reasons, for example.
Some content management systems allow consumers to register a fixed amount of devices which are allowed to consume the content. The identity of those consumption devices is usually checked when they access the content.